A variety of products such as gowns, sheets, drapes, instruments, etc. which are required during surgery or other aseptic procedures, are used on a daily basis in the normal operation of hospitals, clinics and the like. Where such products are not pre-packaged in a sterile state, it is necessary for the hospital or clinic to sterilize them before use. Furthermore, where these products are not disposable, and are employed more than once, it is necessary that they be cleaned and otherwise prepared for subsequent use. Prior to such use, however, it is essential that such products be sterilized.
Due to the volume of materials involved, it is often necessary to sterilize and store these products for later use. Accordingly, there has been developed a procedure where such products, after cleaning, laundering and the like, are packaged in cloth sterilization wrappers and the wrapped package is then sterilized and stored for subsequent use. As may be apparent, there is a potential danger in such a procedure. There is a prospect of unsterilized packages becoming mixed with sterilized packages when stored for use.
To prevent unsterilized products from being used by the physician or attendant, various types of sterility indicators have been developed which are attached to, or incorporated into, the wrapped sterilization package. This permits a user to immediately determine whether a particular package has been passed through the sterilizer. Such sterilization indicators have, in many instances, been placed in the wrapped package or attached to the wrapped package. The most convenient way of applying such sterilization indicators, however, is to have the indicator carried by pressure sensitive adhesive indicator tapes used for holding the cloth wrapper in a closed position prior to, during, and after sterilization of the enclosed products.
Various pressure sensitive adhesives have been used with tape backings that include appropriate color changing means to indicate if the package has been exposed to sterilization conditions. Examples of pressure sensitive adhesives employed with such indicator tapes include water insoluble natural rubber-based adhesives, natural rubber and synthetic rubber blend adhesives, styrene-isoprene-styrene block copolymers with tackifying resins, vinyl ethers, and high molecular weight acrylate copolymers having minimal amounts of plasticizing monomers included therein. See e.g., U.S. Pat. Nos. 2,889,799, 3,067,057, 3,078,182, 3,311,084, and 4,188,437. Typically, these indicator tapes use a paper, fabric or film backing, and an adhesive chemistry that is resistant to softening upon exposure to sterilization conditions (including heat, steam or other chemical methods).
Cloth sterilization wrappers may be disposed of or retained after use. If retained, the soiled cloth wrappers must be cleaned, usually by laundering in soapy water, such as an aqueous alkali solution. These wrappers will then be reused. The expense of some cloth wrappers, such as treated synthetic wrappers and untreated wrappers, demands that the closure and sterilization indicator tapes not damage the wrapper after use.
The various indicator tapes referenced above are not formulated to disperse during cleaning, and in fact, if not manually removed before laundering, may permanently damage a sterilization wrapper. Specifically, the heat and chemicals associated with laundering and drying of the sterilization wrappers will cause the pressure sensitive adhesives used with the indicator tapes to transfer into the fabric of the cloth wrappers, and thereby permanently damage the sterilization wrapper.
In addition, in the various indicator tapes referenced above, there is the potential that the sterilization indicating portion of the indicator tape, which typically contains heavy metals, will be discharged into the waste stream if not removed before laundering.
Water-dispersible pressure sensitive adhesives have been made and used for paper making and printing operations which require splicing of the end of one row of paper to the beginning of another row. For example, U.S. Pat. Nos. 3,865,770, 4,413,080, 4,569,960, 3,441,430, and 2,838,421 disclose such water-dispersible pressure sensitive adhesives and/or splicing tapes made therefrom. Further examples of water-soluble or water-dispersible pressure sensitive adhesive compositions and/or tapes made therefrom can be found in U.S. Pat. Nos. 4,413,082, 4,341,680, 4,388,432, 3,890,292, 3,763,117, 3,152,940, 3,096,202, and European Patent Publication Nos. 0 352 442 and 0 297 451. In addition, U.S. patent application No. 07/580,116 describes an autoclavable water-dispersible pressure sensitive adhesive on a dispersible backing for use as a means to adhere cloth to cloth or cloth to skin in areas where high amounts of fluid would be present.
U.S. patent application Nos. 07/889,647 and 08/257,947 provide a sterilization indicator tape which utilizes a water-dispersible, pressure sensitive adhesive. These indicator tapes include a non-water-dispersible backing which includes thereon a sterilization indicator, and a moisture resistant, water-dispersible, pressure sensitive adhesive coating on at least one of two opposing sides of the non-water-dispersible backing. Such a construction permits laundering of sterilization wrappers without having to remove the indicator tape prior to laundering. The tapes are capable of maintaining a wrapped bundle of articles in a closed position during sterilization, and normal pre- and post-sterilization handling. The water-dispersible, pressure sensitive adhesive on the indicator tapes, however, will disperse upon immersion in the aqueous alkali laundering solutions during laundering, while the tape backing containing the sterilization indicator, such as an indicator ink, stays in tact. Although this type of sterilization indicator tape permits laundering of sterilization wrappers without removal of the indicator tape, the sterilization indicator material (typically containing heavy metals) is introduced into the laundering process and potentially into the waste stream. The non-water-dispersible backing containing the sterilization indicator portion remains intact, and must be collected from laundering equipment following the laundering procedure. Following laundering, the tape can be collected, and disposed.
To date, no indicator tapes utilizing an indicator portion which is easily removable prior to laundering of a sterilization wrapper exist. Thus, present indicator tapes containing sterilization indicator portions, must be collected from industrial laundering equipment following the laundering of sterilization wrappers.